/*
 * Copyright 2020 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package androidx.paging

import androidx.paging.LoadState.NotLoading
import androidx.paging.TestPagingSource.Companion.ITEMS

internal fun createRefresh(range: IntRange, combinedLoadStates: CombinedLoadStates) =
    PageEvent.Insert.Refresh(
        pages = pages(0, range),
        placeholdersBefore = range.first.coerceAtLeast(0),
        placeholdersAfter = (ITEMS.size - range.last - 1).coerceAtLeast(0),
        sourceLoadStates = combinedLoadStates.source,
        mediatorLoadStates = combinedLoadStates.mediator,
    )

internal fun createRefresh(
    range: IntRange,
    startState: LoadState = NotLoading.Incomplete,
    endState: LoadState = NotLoading.Incomplete,
) =
    PageEvent.Insert.Refresh(
        pages = pages(0, range),
        placeholdersBefore = range.first.coerceAtLeast(0),
        placeholdersAfter = (ITEMS.size - range.last - 1).coerceAtLeast(0),
        sourceLoadStates = loadStates(prepend = startState, append = endState),
        mediatorLoadStates = null,
    )

internal fun createPrepend(
    pageOffset: Int,
    range: IntRange,
    startState: LoadState = NotLoading.Incomplete,
    endState: LoadState = NotLoading.Incomplete,
) =
    PageEvent.Insert.Prepend(
        pages = pages(pageOffset, range),
        placeholdersBefore = range.first.coerceAtLeast(0),
        sourceLoadStates = loadStates(prepend = startState, append = endState),
        mediatorLoadStates = null,
    )

internal fun createAppend(
    pageOffset: Int,
    range: IntRange,
    startState: LoadState = NotLoading.Incomplete,
    endState: LoadState = NotLoading.Incomplete,
) =
    PageEvent.Insert.Append(
        pages = pages(pageOffset, range),
        placeholdersAfter = (ITEMS.size - range.last - 1).coerceAtLeast(0),
        sourceLoadStates = loadStates(prepend = startState, append = endState),
        mediatorLoadStates = null,
    )

private fun pages(pageOffset: Int, range: IntRange) =
    listOf(TransformablePage(originalPageOffset = pageOffset, data = ITEMS.slice(range)))
